To not offer to take friends dc to cinema

I am supposed to be taking my dc to the cinema in 3d with a small group of friends One friend can't make it and I could offer to take her dc with me as in the past I have babysat him a fair bit but I don't want to because

1. He is badly behaved in the cinema and I would be constantly telling him to sit down and not enjoy myself on what's a rare treat for me and my Ds. My Ds is second born and rarely gets one to one treats with me2. Last time I baby sat him he called me an idiot and upset my dd3. Last time I saw him he called another adult friend an idiot in an aggressive manner because she tickled him. 4. He has been swearing in front of my 3 yo who has repeated the words

I just feel bad on his mother who is great and very obliging but presently I find her Ds extremely difficult. Aibu? And should I make an excuse or say nothing

Usually it would be my dd and Ds going together with me sometimes with other friends but she is on a play date so won't be around So it is rare for him to have just me take him to an event Regardless of other company

My friend has offered to take my Ds and dd to similar events if I can't go in the past. But in the last six months her Ds behaviour has got worse and worse

I would say nothing. Other people's kids in the cinema can be a pain. I'll do it if I know they'll do as they are told but otherwise only when it's one of my kids' birthdays and that is the thing they want to do.Your friend can just take her son another time. She is the one who has decided she has other priorities.